To investigate the variation of plantar dynamics in paratroopers landing on different ground conditions.

German Pedar-X system was used to measure the dynamic indexes of 20 active-duty parachutists from " August 1st" Skydiving Team, who simulated the jump from 60 cm-high platform as the paratroopers, and landed on the hard and soft ground, respectively, and the maximum stress, maximum pressure, and maximum pressure-time integral were recorded. The left and right plantar were divided into 10 regions. The variation of the plantar on the ground of two different conditions was determined. The differences of the plantar maximum stress of the two ground conditions were compared.

The maximum stress distribution of left and right plantar on the hard and soft ground was: regions 9-10> region 8> regions 1-7, respectively. Compared with the maximum hind-plantar stress, there were statistically significant differences between the maximum plantar stresses of the two ground conditions (P<0.05). The distribution of the maximum pressure and maximum stress of the left and right plantar was consistent. Compared with the maximum right hind-plantar stress, there were statistically significant differences between the maximum plantar stresses of the two ground conditions (P<0.05). There was a statistically significant difference between the time integral of left and right fore-plantar on hard and sandy ground, respectively (P<0.05).

The maximum pressure and maximum stress of hind-plantar of half squat-style landing on hard ground were significantly higher than those of fore-plantar of half squat-style landing on soft ground. There are differences in the maximum pressure and maximum stress between half squat-style landing on hard and soft ground. Compared with hard ground, landing with half squat-style on soft ground is not easy to injure heels.

Chinese paratroopers; plantar; Pedar-X system; dynamic indext